Creation and Validation of a Novel 3-Dimensional Pediatric Hip Ultrasound Model.

OBJECTIVES: The aim of this study was to create and validate a 3-dimensional (3D) ultrasound model with normal and abnormal pediatric hip joint anatomy that is comparable to a pediatric hip joint in appearance and anatomy and replicates sonographic characteristics of a pediatric hip joint. METHODS: A 3D rendering of the bone and soft tissue was created from a computed tomography pelvic scan of a pediatric patient. This rendering was modified to include a unilateral joint effusion. The bone was 3D printed with a photopolymer plastic, whereas the soft tissue was cast with a silicone mixture in a 3D-printed mold. The effusion was simulated by injecting saline into the soft tissue cavity surrounding the bone. The ultrasound model was validated by pediatric point-of-care ultrasonographers at an international pediatric ultrasound conference. RESULTS: A pediatric hip ultrasound model was developed that simulates both normal and abnormal pediatric hip joint anatomy, each with an appropriately sized, measurable joint effusion. Validation by pediatric point-of-care ultrasonographers showed that the key aspects of a normal pediatric hip joint (femoral physis, sloped femoral neck, and adequate soft tissue) with an identifiable and measurable effusion were included in the ultrasound model. CONCLUSIONS: In this study, we successfully created a cost-effective, reusable, and reproducible 3D pediatric hip ultrasound model. The majority of pediatric point-of-care ultrasonographers who evaluated the model agreed that this model is comparable to a pediatric patient for the purpose of teaching ultrasound skills and joint space measurement.

Point-of-Care Ultrasound, an Unexpected Cardiac Mass in a Neonate.

ABSTRACT: Neonatal cardiac masses are uncommon and often not obvious based on physical examination or plain radiography. The objective of this clinical case report is to demonstrate how cardiac point-of-care ultrasound was pivotal in the clinical course of a seemingly well neonate with vague symptoms. A 6-week-old male infant presented to the emergency department with fatigue and pallor that was reported to have resolved before arrival. In the emergency department, he had a normal physical examination and stable vital signs. Cardiac point-of-care ultrasound was performed and demonstrated a mass near the mitral valve. These ultrasound findings prompted additional evaluation, cardiology consultation, admission, and subsequent diagnosis of a rhabdomyoma due to tuberous sclerosis.

Point-of-Care Ultrasound Assessment of Orbital Rhabdomyosarcoma in a Pediatric Patient.

ABSTRACT: Rhabdomyosarcoma is the most common soft tissue tumor in children and orbital lesions account for 10% of these diagnoses. This case describes a young boy who presented with eyelid swelling that was initially concerning for an expanding hematoma given a history of recent trauma to the eye. Point-of-care ultrasound identified 2 distinct lesions surrounding the globe, which prompted further investigation, including ophthalmology consult and computed tomography. The case presented highlights the initial misdiagnosis on both point-of-care ultrasound and computed tomography and the importance of using color Doppler on ultrasound to distinguish an orbital rhabdomyosarcoma from a posttraumatic hematoma.

The Human Leukocyte Antigen (HLA)-B27 Peptidome in Vivo, in Spondyloarthritis-susceptible HLA-B27 Transgenic Rats and the Effect of Erap1 Deletion.

HLA-B27 is a class I major histocompatibility (MHC-I) allele that confers susceptibility to the rheumatic disease ankylosing spondylitis (AS) by an unknown mechanism. ERAP1 is an aminopeptidase that trims peptides in the endoplasmic reticulum for binding to MHC-I molecules. ERAP1 shows genetic epistasis with HLA-B27 in conferring susceptibility to AS. Male HLA-B27 transgenic rats develop arthritis and serve as an animal model of AS, whereas female B27 transgenic rats remain healthy. We used large scale quantitative mass spectrometry to identify over 15,000 unique HLA-B27 peptide ligands, isolated after immunoaffinity purification of the B27 molecules from the spleens of HLA-B27 transgenic rats. Heterozygous deletion of Erap1, which reduced the Erap1 level to less than half, had no qualitative or quantitative effects on the B27 peptidome. Homozygous deletion of Erap1 affected approximately one-third of the B27 peptidome but left most of the B27 peptidome unchanged, suggesting the possibility that some of the HLA-B27 immunopeptidome is not processed in the presence of Erap1. Deletion of Erap1 was permissive for the AS-like phenotype, increased mean peptide length and increased the frequency of C-terminal hydrophobic residues and of N-terminal Ala, Ser, or Lys. The presence of Erap1 increased the frequency of C-terminal Lys and Arg, of Glu and Asp at intermediate residues, and of N-terminal Gly. Several peptides of potential interest in AS pathogenesis, previously identified in human cell lines, were isolated. However, rats susceptible to arthritis had B27 peptidomes similar to those of non-susceptible rats, and no peptides were found to be uniquely associated with arthritis. Whether specific B27-bound peptides are required for AS pathogenesis remains to be determined. Data are available via ProteomeXchange with identifier PXD005502.